[RFC,v5,2/4] fpga: add fake FPGA bridge

  Add fake FPGA bridge platform driver with support functions. This module
is part of the KUnit tests for the FPGA subsystem.

Signed-off-by: Marco Pagani <marpagan@redhat.com>
---
 drivers/fpga/tests/fake-fpga-bridge.c | 203 ++++++++++++++++++++++++++
 drivers/fpga/tests/fake-fpga-bridge.h |  40 +++++
 2 files changed, 243 insertions(+)
 create mode 100644 drivers/fpga/tests/fake-fpga-bridge.c
 create mode 100644 drivers/fpga/tests/fake-fpga-bridge.h
  

On 2023-05-11 at 16:19:20 +0200, Marco Pagani wrote:
> Add fake FPGA bridge platform driver with support functions. This module
> is part of the KUnit tests for the FPGA subsystem.
> 
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> ---
>  drivers/fpga/tests/fake-fpga-bridge.c | 203 ++++++++++++++++++++++++++
>  drivers/fpga/tests/fake-fpga-bridge.h |  40 +++++
>  2 files changed, 243 insertions(+)
>  create mode 100644 drivers/fpga/tests/fake-fpga-bridge.c
>  create mode 100644 drivers/fpga/tests/fake-fpga-bridge.h
> 
> diff --git a/drivers/fpga/tests/fake-fpga-bridge.c b/drivers/fpga/tests/fake-fpga-bridge.c
> new file mode 100644
> index 000000000000..e5db0a809ee3
> --- /dev/null
> +++ b/drivers/fpga/tests/fake-fpga-bridge.c
> @@ -0,0 +1,203 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for the fake FPGA bridge
> + *
> + * Copyright (C) 2023 Red Hat, Inc.
> + *
> + * Author: Marco Pagani <marpagan@redhat.com>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/fpga/fpga-bridge.h>
> +#include <kunit/test.h>
> +
> +#include "fake-fpga-bridge.h"
> +
> +#define FAKE_FPGA_BRIDGE_DEV_NAME	"fake_fpga_bridge"
> +
> +struct fake_bridge_pdata {
> +	struct kunit *test;
> +	struct fake_fpga_bridge_stats *stats;
> +};
> +
> +struct fake_bridge_priv {
> +	bool state;
> +	struct fake_bridge_pdata *pdata;
> +};
> +
> +static int op_enable_show(struct fpga_bridge *bridge)
> +{
> +	struct fake_bridge_priv *priv;
> +
> +	priv = bridge->priv;
> +
> +	kunit_info(priv->pdata->test, "Fake FPGA bridge %u: enable_show\n",
> +		   bridge->dev.id);
> +
> +	return priv->state;
> +}
> +
> +static int op_enable_set(struct fpga_bridge *bridge, bool enable)
> +{
> +	struct fake_bridge_priv *priv;
> +
> +	priv = bridge->priv;
> +
> +	if (enable && !priv->state)
> +		priv->pdata->stats->cycles_count++;
> +
> +	priv->state = enable;
> +	priv->pdata->stats->enable = priv->state;
> +
> +	kunit_info(priv->pdata->test, "Fake FPGA bridge %u: enable_set: %d\n",
> +		   bridge->dev.id, enable);
> +
> +	return 0;
> +}
> +
> +static void op_remove(struct fpga_bridge *bridge)
> +{
> +	struct fake_bridge_priv *priv;
> +
> +	priv = bridge->priv;
> +
> +	kunit_info(priv->pdata->test, "Fake FPGA bridge %u: remove\n",
> +		   bridge->dev.id);
> +}
> +
> +static const struct fpga_bridge_ops fake_fpga_bridge_ops = {
> +	.enable_show = op_enable_show,
> +	.enable_set = op_enable_set,
> +	.fpga_bridge_remove = op_remove,
> +};
> +
> +/**
> + * fake_fpga_bridge_register() - register a fake FPGA bridge.
> + * @test: KUnit test context object.
> + * @parent: parent device.
> + *
> + * Return: pointer to a new fake FPGA bridge on success, an ERR_PTR()
> + * encoded error code on failure.
> + */
> +struct fake_fpga_bridge *
> +fake_fpga_bridge_register(struct kunit *test, struct device *parent)
> +{
> +	struct fake_fpga_bridge *bridge_ctx;
> +	struct fake_bridge_pdata pdata;
> +	struct fake_bridge_priv *priv;
> +	int ret;
> +
> +	bridge_ctx = kunit_kzalloc(test, sizeof(*bridge_ctx), GFP_KERNEL);
> +	if (!bridge_ctx) {
> +		ret = -ENOMEM;
> +		goto err_mem;
> +	}
> +
> +	bridge_ctx->pdev = platform_device_alloc(FAKE_FPGA_BRIDGE_DEV_NAME,
> +						 PLATFORM_DEVID_AUTO);
> +	if (!bridge_ctx->pdev) {
> +		pr_err("Fake FPGA bridge device allocation failed\n");
> +		ret = -ENOMEM;
> +		goto err_mem;
> +	}
> +
> +	pdata.test = test;
> +	pdata.stats = &bridge_ctx->stats;
> +	platform_device_add_data(bridge_ctx->pdev, &pdata, sizeof(pdata));
> +
> +	bridge_ctx->pdev->dev.parent = parent;
> +	ret = platform_device_add(bridge_ctx->pdev);
> +	if (ret) {
> +		pr_err("Fake FPGA bridge device add failed\n");
> +		goto err_pdev;
> +	}
> +
> +	bridge_ctx->bridge = platform_get_drvdata(bridge_ctx->pdev);
> +
> +	priv = bridge_ctx->bridge->priv;
> +	bridge_ctx->stats.enable = priv->state;
> +
> +	kunit_info(test, "Fake FPGA bridge %u: registered\n",
> +		   bridge_ctx->bridge->dev.id);
> +
> +	return bridge_ctx;
> +
> +err_pdev:
> +	platform_device_put(bridge_ctx->pdev);
> +err_mem:
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(fake_fpga_bridge_register);

Same as fake_fpga_mgr.

Thanks,
Yilun

> +
> +/**
> + * fake_fpga_bridge_unregister() - unregister a fake FPGA bridge.
> + * @bridge_ctx: fake FPGA bridge context data structure.
> + */
> +void fake_fpga_bridge_unregister(struct fake_fpga_bridge *bridge_ctx)
> +{
> +	struct fake_bridge_priv *priv;
> +	struct kunit *test;
> +	u32 id;
> +
> +	if (!bridge_ctx)
> +		return;
> +
> +	id = bridge_ctx->bridge->dev.id;
> +	priv = bridge_ctx->bridge->priv;
> +	test = priv->pdata->test;
> +
> +	platform_device_unregister(bridge_ctx->pdev);
> +
> +	kunit_info(test, "Fake FPGA bridge %u: unregistered\n", id);
> +}
> +EXPORT_SYMBOL_GPL(fake_fpga_bridge_unregister);
> +
> +static int fake_fpga_bridge_probe(struct platform_device *pdev)
> +{
> +	struct device *dev;
> +	struct fake_bridge_pdata *pdata;
> +	struct fpga_bridge *bridge;
> +	struct fake_bridge_priv *priv;
> +
> +	dev = &pdev->dev;
> +	pdata = dev_get_platdata(dev);
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->pdata = pdata;
> +	priv->state = true;
> +
> +	bridge = fpga_bridge_register(dev, "Fake FPGA Bridge",
> +				      &fake_fpga_bridge_ops, priv);
> +	if (IS_ERR(bridge))
> +		return PTR_ERR(bridge);
> +
> +	platform_set_drvdata(pdev, bridge);
> +
> +	return 0;
> +}
> +
> +static int fake_fpga_bridge_remove(struct platform_device *pdev)
> +{
> +	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
> +
> +	fpga_bridge_unregister(bridge);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver fake_fpga_bridge_drv = {
> +	.driver = {
> +		.name = FAKE_FPGA_BRIDGE_DEV_NAME
> +	},
> +	.probe = fake_fpga_bridge_probe,
> +	.remove = fake_fpga_bridge_remove,
> +};
> +
> +module_platform_driver(fake_fpga_bridge_drv);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/fpga/tests/fake-fpga-bridge.h b/drivers/fpga/tests/fake-fpga-bridge.h
> new file mode 100644
> index 000000000000..3ecfab7e2890
> --- /dev/null
> +++ b/drivers/fpga/tests/fake-fpga-bridge.h
> @@ -0,0 +1,40 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Header file for the fake FPGA bridge
> + *
> + * Copyright (C) 2023 Red Hat, Inc.
> + *
> + * Author: Marco Pagani <marpagan@redhat.com>
> + */
> +
> +#ifndef __FPGA_FAKE_BRIDGE_H
> +#define __FPGA_FAKE_BRIDGE_H
> +
> +#include <linux/types.h>
> +#include <linux/platform_device.h>
> +#include <kunit/test.h>
> +
> +struct fake_fpga_bridge_stats {
> +	bool enable;
> +	u32 cycles_count;
> +};
> +
> +/**
> + * struct fake_fpga_bridge - fake FPGA bridge context data structure
> + *
> + * @bridge: FPGA bridge.
> + * @pdev: platform device of the FPGA bridge.
> + * @stats: info from the low level driver.
> + */
> +struct fake_fpga_bridge {
> +	struct fpga_bridge *bridge;
> +	struct platform_device *pdev;
> +	struct fake_fpga_bridge_stats stats;
> +};
> +
> +struct fake_fpga_bridge *
> +fake_fpga_bridge_register(struct kunit *test, struct device *parent);
> +
> +void fake_fpga_bridge_unregister(struct fake_fpga_bridge *bridge_ctx);
> +
> +#endif /* __FPGA_FAKE_BRIDGE_H */
> -- 
> 2.40.1
>